1. Field of the Invention
A door closing system for subsequent installation on an automatic sliding door of an elevator car which, at floor stops, is coupled via cams and couplings with the hoistway door and is opened and closed together therewith, wherein the closing system prohibits opening and closing of the elevator door from the interior of the car when the latter is between two floors, i.e., beyond the door opening zone of a floor.
2. Discussion of the Background of the Invention and Material Information
Automatic door systems on elevators which conform to the current state of the art and to current regulations are constructed and equipped to meet the retirement that elevator passengers be unable to open the car door when the car is beyond the door opening zone of a floor. Since these retirements and regulations are not very old there remain very many elevator installations that no longer meet these terms, but however are still fully functional and operational for years to come.
The door systems of such elevator installations must however be adapted to the present regulations which presents the problem of a practical and cost effective solution. Generally, it is desired to update the non-regulation conforming door systems to the currently required safety standard with the smallest possible intrusion into the existing construction and with the use of the fewest additional parts.
U.S. Pat. No. 4,313,525 presents such a solution. However, it pertains to an automatic elevator sliding door of nodal known construction. A horizontally reversible coupling arrangement on the car door is brought to an operating position by the door drive in front of a stop and at the door opening zone of a floor stop, with the use thereof of a clutched coupling and unlocking rollers, the hoistway and car doors are opened. At the beginning of the opening sequence the right coupling cam on the car door touches the right unlocking roller of the hoistway door. In the further process of the opening movement, the right coupling cam, journalled in a parallelogram, is pressed to the right and simultaneously is lifted upwardly. A vertical connecting rod, mechanically coupled with the right coupling cam is also moved upwardly and lifts a locking pawl from an engaged position, whereby the car door is mechanically unlocked.
The thus described solution is directed to fulfilling the previously noted requirements. A general utilization appears to be impossible however, since for the unlocking of a member, vertical movement in engagement with the hoistway door is required, so that the presented solution is obviously not usable for universal subsequent installation.